Anyway I can make this work somehow ?

fun <T> foo(aClass: java.lang.Class<T>): MutableList<T> {
  return mutableListOf()
}

inline fun <reified T:Any> bar(t: T): MutableList<T> {
  // fails here: expected: MutableList<T>, found: MutableList<out T>
  return foo(t::class.java) 
}

Not really, it just doesn't make sense:

t

could have a subtype of

T

, and so

t::class.java

could be a subclass of

Class<T>

and a

MutableList

is invariant. The only thing you can do is make

bar

return

MutableList<out T>

which is correct.

t

could have a subtype of

T

right, thanks !